No point-and-click solution that I know, but I found a solution modifying the file :


~/.thunderbird//prefs.js


look for the line :

user_pref("mail.accountmanager.accounts", "account1,account2,account3,account4,account6,account5,account7,account8,account10");


And re-order the "accountX" as you wish to see them.


Be careful to edit this file while thunderbird is NOT running, it seems that tb writes this file back at the exit.